High performance organic light-emitting diodes fabricated via a vacuum-free lamination process

We demonstrate high performance organic light-emitting diodes (OLEDs) fabricated via a vacuum-free, direct lamination process. The OLEDs were made by laminating an anode component to a separately engineered cathode component using a roll laminator. We further present a solution-based chemical n-doping strategy to enable efficient electron injection from an inert cathode into polymeric organic semiconductors. The n-doping strategy is demonstrated by chemically reducing a conjugated light-emitting polymer with an alkali metal in an organic solvent. The metal reduced conjugated polymer, when employed as an electron injection layer, yields laminated OLEDs with efficiency comparable to conventionally fabricated devices utilizing a vacuum-deposited, reactive metal cathode. These designs and techniques should enable applications such as lighting where extremely low cost device fabrication is required.